Insomnia

I find my sleeping patterns are changing. For a long while I took two naps per day, one in the morning and one in the early afternoon. Then I migrated to one nap in the early afternoon. Unfortunately for my parents, my sleep schedule seems to have shifted again. Now I prefer to nap from about 3:00 until 5:00 pm. I've been doing this for about a week, and I've been having trouble sleeping at night. I'm happy enough to go to bed around 8-8:30 (my usual bedtime), but I find myself waking up and not being happy about it during the last few nights. Worse yet, it's hard for me to fall back to sleep once I'm up. While this hasn't had much effect on my usual sunny demeanor during the day, Mommy says it's killing her. Daddy says something about my "circadian rhythms" being off. I don't know what that is, but it doesn't sound like a good thing.